With development of intelligent terminals, more application software can run on an intelligent terminal, so that a terminal user can send an email, access a social network, make payment on a terminal, and run various application games by using the intelligent terminal. In a process of running application software by the intelligent terminal, a large amount of user data is generated, including state data generated in real time during runtime of the application software and file data stored on a disk after running of the application software. These data possibly involves privacy of the terminal user. When the intelligent terminal is lost, user data in the intelligent terminal is also lost accordingly, or when the intelligent terminal is infected with malicious software, the user data in the intelligent terminal is at risk. Therefore, in order to protect completeness of data on the intelligent terminal and user privacy, the intelligent terminal may, by performing mirror synchronization with a cloud server, enable the cloud server to obtain the user data on the intelligent terminal, so as to back up the user data of the intelligent terminal and perform security check on the user data by using abundant computing resources on the cloud server.
In the prior art, the intelligent terminal may transmit the file data generated after the running of the application software to the cloud server through a network. However, because real-time state data during the running of the application software cannot be synchronized in such a synchronization manner, the user data backed up by the cloud server is incomplete, and accordingly, security check based on the user data is also inaccurate.